After your first comment Trombi I was very surprised to read the second. Maybe some sarcasm didn't come across! A decent, playable, long lasting new flute for 85 euros? It has to be a heap of ....

If think that the best flute for her is an Yamaha, but if she don' t want to pay for it, a flute from Thomanns is at least a flute that can be played on even if it cost only 85 Euro. If she buy a flute from ebay she might have to pay more to repair it than her whole budget.

Used is better if they're just starting and you have no idea if they're going to stick with it. Our local music store also had a rent to own program, which is how we paid for mine. It ultimately ended up costing in the $400 range, but that was over about 2 years. If I'd decided to stop playing at any point in time, we would have returned it and that would have been the end of it. Also, my school had some instruments available for students to rent as well. Regardless of whether your daughters will be playing at school or taking private lessons, ask the director/instructor if that's an option. It may not be, but some will have a limited number available if needed. They may only do so if it's a financial issue, though, where you legitimately could not afford to buy one. It depends.

My suggestion is to see if there's anywhere in your area that can offer that, and go for the highest end you can that way. Like other people have said, instrument quality is very important and you do NOT want to just get the cheapest available in case they decide to quit. Buy used, but buy high quality. The most common brands at my school were Yamaha and Gemeinhardt, if that helps any.

As a side note, I'd also have to disagree with the people who say 8 is very young to learn. My elementary school music program began in 4th grade, when most kids were 9. I know very few people who were older than 9 or 10 when they started playing. Just...don't expect them to sound very good for awhile.